掺杂硫化铅体系的电子性质研究

基于密度泛函理论和广义梯度近似，对掺杂PbS体系进行了电子性质的第一性原理计算. 首先，对恒定掺杂浓度(6.25%)时3种替换杂质(Cd、Sn、Sb)不同掺杂位置的形成能进行比较分析，得到了最稳定的掺杂结构. 然后，计算不同掺杂体系的能带结构，能带结构发生了平移，带隙随掺杂原子序数单调递减. 最后，研究掺杂前后光学性质，光学性质的显著变化出现在Sb掺杂的PbS体系中，主要包括介电光谱下杂质峰的出现、相关红移现象以及掺杂后吸收谱能带边缘的拓展. 同时，Cd掺杂PbS介电光谱的反射峰最小.

Investigation of Electronic Property for Doped PbS System

The first principles calculations of electronic property for doped PbS are investigated based on the density functional theory and generalized gradient approximation. Firstly, among the three substitutional impurities (Cd, Sn, Sb) with constant dopant concentration, the most stable structure is obtained through the analysis of the formation energy for different doping position. Then, the band structures of three doped systems are calculated. It is found that the band gaps decrease monotonically with the impuritys atomic number after doping, in addition to the shifted band structures. Finally, the optical properties of three doped systems are obtained, mainly including the impurity peak and the red shifted peak in the dielectric functions, and the expansion of absorption band ranges for doped systems. The lowest reflectivity peak arises in Cd doped PbS.